I really depens on how much movement your going to have,if up and down is only going to be about 2in. max,then go for panhard[always as long as canbe fitted.
But if you've got 3 or more in. then a watts is good.
The deal is how much side to side is done when panhard moves up and down=in small up down,you got so tiny side to side it dose not mess with anything.